It's difficult to prove because there have been drive shaft issues even with stock diff cover. If that were the case, I could ask VAC for reimbursement of repair costs but I know that they will deny deny deny.

It's difficult to prove because there have been drive shaft issues even with stock diff cover. If that were the case, I could ask VAC for reimbursement of repair costs but I know that they will deny deny deny.

I'm not sure but BuraQ actually had an entire pumpkin changed. I think dzenno as well. Every case is unique tho but if I were trying to prove the cover came first, I'd have to hire some CSI type folks and carbon date the pieces. LOL, of course I'm BSing here.

The diff housing would be almost completely unloaded if the shaft broke first. There would be no force to break the housing. It makes much more sense for the shock of the downshift to cause the housing to break which caused the shaft to be damaged.

Regardless, this is my opinion, though an educated one. I hope you get the car back on the road soon.

I don't think it will be that serious. The case should not crack period. It doesn't make any sense that the driveshaft breaking would snap a case. Its the other way around. If the case snaps, the angle will surely wreak havoc with the driveshaft. If anything I would be more worried about getting cover+driveshaft money back. Explain that the cover can't crack if the driveshaft isn't attached, if they don't see it that way, let the public know. How big of a market is there for overpriced diff covers that crack? Obviously put your best foot forward and be friendly/reasonable about it.

I don't think it will be that serious. The case should not crack period. It doesn't make any sense that the driveshaft breaking would snap a case. Its the other way around. If the case snaps, the angle will surely wreak havoc with the driveshaft. If anything I would be more worried about getting cover+driveshaft money back. Explain that the cover can't crack if the driveshaft isn't attached, if they don't see it that way, let the public know. How big of a market is there for overpriced diff covers that crack? Obviously put your best foot forward and be friendly/reasonable about it.

couldn't have said it better myself. all the clues exist in the broken pieces...basic chicken/egg argument lol...

I don't think so but I mean do we expect a diff cover to be able to withstand whatever stress is thrown at it from any which way?

Absolutely not; but this diff didn't experience any force it wasn't meant to handle. (Like a crash, or hitting something on the road.)
Perhaps the argument can be made that @blisstik was such a prolific launcher (was he?) that he wheel-hopped tiny stress fractures into his diff cover, a feat that nobody has published among the OEM cover broken driveshaft/cv crowd, and then those stress fractures let the ear go and the diff rotated out and nuked the driveshaft.

Even if my diff cover saw all day insane ridiculous launches it should be engineered to withstand those forces, that's its primary job. I expect that to be even more true when dealing with a shop that has a reputation to performance like VAC.

Absolutely not; but this diff didn't experience any force it wasn't meant to handle. (Like a crash, or hitting something on the road.)
Perhaps the argument can be made that @blisstik was such a prolific launcher (was he?) that he wheel-hopped tiny stress fractures into his diff cover, a feat that nobody has published among the OEM cover broken driveshaft/cv crowd, and then those stress fractures let the ear go and the diff rotated out and nuked the driveshaft.

Even if my diff cover saw all day insane ridiculous launches it should be engineered to withstand those forces, that's its primary job. I expect that to be even more true when dealing with a shop that has a reputation to performance like VAC.

Absolutely not; but this diff didn't experience any force it wasn't meant to handle. (Like a crash, or hitting something on the road.)
Perhaps the argument can be made that @blisstik was such a prolific launcher (was he?) that he wheel-hopped tiny stress fractures into his diff cover, a feat that nobody has published among the OEM cover broken driveshaft/cv crowd, and then those stress fractures let the ear go and the diff rotated out and nuked the driveshaft.

Even if my diff cover saw all day insane ridiculous launches it should be engineered to withstand those forces, that's its primary job. I expect that to be even more true when dealing with a shop that has a reputation to performance like VAC.

If you're going to charge as much as they do for a diff cover, it should be a non-issue. I don't know why anyone buys these covers anyway (at those prices). If you really are getting excessive temps just tap the stock over and run an external cooler...

I'm sorry, I was mistakenly thinking that the rear axle was what broke. I thought the left rear axle broke off and hit the differential cover.

After looking more closely, it appears the VAC differential cover broke where it attaches to the car. After looking at the differential cover:

it looks like where it broke is the the weakest structural point on the differential cover.

In my opinion, a 3rd gear to 2nd gear downshift doesn't generate enough power to snap a drive shaft. It seems more logical that the differential cover broke first causing the drive shaft to move in all sorts of ways.

I was thinking the the cover was acted upon externally but I'm not sure if we should jump to defect. Parts break, let's see what VAC does.

Yeah, that's what I thought at first too. But seeing how the rear axle didn't break, I can't think of anything else on the car hitting that part. Unless it was something on the road that the differential got caught on, but I'd guess there would be damage on the bottom of the differential as well.

Who knows, maybe the bolt was overly-tightened? Either way, considering VAC's great reputation, I'm sure they will take care of this no problem.